From time immemorial, plants have been the focus of religious life for many people in the world. Plants are praised and honored by people because of their close association with a deity. Some plants gained religious importance because of their efficacious use in religious ceremonies, rituals, festivals, and poojas. While certain plants are sacred because of their close association with particular locations such as temples, many others are associated with constellations (Nakshatras) and planets (Grahas). Many plants sacred to an area are also revered in other parts of India. It has found that in Assam about 205 species belonging to 178 genera under 72 families are being used in various cultural and religious practices. Moreover, it has also been recorded in the present book that the most frequently used plant families in religious practices are Asteraceae, Poaceae, Rubiaceae, Verbenaceae, Zingiberaceae and Leguminosae. Leaf, seed, fruit, bark, wood, flower, roots, whole plant, Rhizome and Bulb are used for various religious purposes by the ethnic communities of Assam. This work also reveals the importance of sacred plants in ethnomedicinal aspects. There are also a few myths related to sacred plants in some communities. Apart from being sacred and integral part of biodiversity, these plants also have natural healing properties that can be utilized medicinally. An appropriate strategy for the conservation and sustainable utilization of such plants needs to be developed. Any study on these plants is likely to open new areas of research in the field of medicine, pharmacology, economic botany and conservation biology.